Various wired and wireless traffic monitoring techniques have been used to track the number and the speed of vehicles on a roadway. Among the more popular non-intrusive techniques in use is radar-based traffic monitoring. Yet radar-based traffic monitoring systems face a number of challenges including beam-spreading, multi-path interference, fading, electromagnetic interference, and generally high levels of attenuations. Consequently, many radar systems (even when frequently re-calibrated) routinely exhibit measurement errors exceeding 5%. For a significant fraction of the measurement attempts, many radar systems fail to register any measurement at all.
In repeated attempts to improve the reliability and accuracy of radar-based traffic monitoring, a number of system designs have been proposed. See, e.g., U.S. Pat. No. 7,426,450 “Systems and methods for monitoring speed”, which discloses no less than nine radar-based speed monitoring techniques. Nevertheless, such techniques do not appear to adequately address the ever-increasing demands for improved accuracy and reliability.
It should be understood, however, that the specific embodiments given in the drawings and detailed description below do not limit the disclosure. On the contrary, they provide the foundation for one of ordinary skill to discern the alternative forms, equivalents, and other modifications that are encompassed in the scope of the appended claims.